* ordering of the keys.
   *
   * <p>Despite the method name, this method attempts to avoid actually copying the data when it is
   * safe to do so. The exact circumstances under which a copy will or will not be performed are
   * undocumented and subject to change.
   *
   * <p>This method is not type-safe, as it may be called on a map with keys that are not mutually
   * comparable.
   *

 * UnsupportedOperationException} in the situations they are intended for.
 *
 * <h3>Non-preconditions</h3>
 *
 * <p>It is of course possible to use the methods of this class to check for invalid conditions
 * which are <i>not the caller's fault</i>. Doing so is <b>not recommended</b> because it is
 * misleading to future readers of the code and of stack traces. See <a

      public void run() {
        thirdSignal.countDown();
        result.set(1, cache.getUnchecked(key));
        doneSignal.countDown();
      }
    }.start();

    // give the second get a chance to run; it is okay for this to be racy
    // as the end result should be the same either way
    thirdSignal.await();
    Thread.yield();

    // Expand!
    CacheTesting.forceExpandSegment(cache, key);

  public void testPowerSetIteration_manual() {
    ImmutableSet<Integer> elements = ImmutableSet.of(1, 2, 3);
    Set<Set<Integer>> powerSet = powerSet(elements);
    // The API doesn't promise this iteration order, but it's convenient here.
    Iterator<Set<Integer>> i = powerSet.iterator();
    assertEquals(ImmutableSet.of(), i.next());
    assertEquals(ImmutableSet.of(1), i.next());
    assertEquals(ImmutableSet.of(2), i.next());

    return set;
  }

  /**
   * Creates a {@code LinkedHashSet} instance, with a high enough "initial capacity" that it
   * <i>should</i> hold {@code expectedSize} elements without growth. This behavior cannot be
   * broadly guaranteed, but it is observed to be true for OpenJDK 1.7. It also can't be guaranteed
   * that the method isn't inadvertently <i>oversizing</i> the returned set.
   *

    } else if (obj instanceof Failure) {
      throw new ExecutionException(((Failure) obj).exception);
    } else if (obj == NULL) {
      /*
       * It's safe to return null because we would only have stored it in the first place if it were
       * a valid value for V.
       */
      return uncheckedNull();
    } else {
      @SuppressWarnings("unchecked") // this is the only other option
      V asV = (V) obj;

   *
   * <p>This implementation tries to be smart in a number of ways. It recognizes cases where the
   * negation is cheaper to precompute than the matcher itself; it tries to build small hash tables
   * for matchers that only match a few characters, and so on. In the worst-case scenario, it
   * constructs an eight-kilobyte bit array and queries that. In many situations this produces a

    // way for it to return a false negative would be for the target value to jump around in the map
    // such that none of the subsequent iterations observed it, despite the fact that at every point
    // in time it was present somewhere int the map. This becomes increasingly unlikely as
    // CONTAINS_VALUE_RETRIES increases, though without locking it is theoretically possible.

    step4Waiter.awaitStarted();

    // Step 1 is not cancelled because it was done.
    assertWithMessage("step1.statusFuture().isCancelled()")
        .that(step1.statusFuture().isCancelled())
        .isFalse();
    // But its closeable is closed.
    assertClosed(closeable1);

    // Step 2 is cancelled because it wasn't complete.
    assertWithMessage("step2.statusFuture().isCancelled()")

   * ordering of the keys.
   *
   * <p>Despite the method name, this method attempts to avoid actually copying the data when it is
   * safe to do so. The exact circumstances under which a copy will or will not be performed are
   * undocumented and subject to change.
   *
   * <p>This method is not type-safe, as it may be called on a map with keys that are not mutually
   * comparable.
   *